【作者】 刘欣；

【导师】 王立贤；

【作者基本信息】 中国农业科学院 ， 动物遗传育种与繁殖， 2014， 博士

【摘要】 本研究从基因组水平对猪的重要且复杂的经济性状-胴体性状研究，并筛选背膘厚性状的主效候选基因。本研究构建了大白猪×民猪F2代资源群体，对其应用Illumina Porcine SNP60K BeadChip基因分型，之后对猪的胴体性状进行了全基因组关联分析（Genome-wideAssociation Study, GWAS），并对背膘厚性状的显著区间深入研究筛选主效候选基因。1、对F2资源群体的头重、蹄重、板油重、背膘厚、胴体长、胴体重和屠宰体重七个性状进行描述分析，均值分别为7.52kg,1.69kg,1.46kg,3.84cm,95.58cm,78.96kg and109.11kg。2、根据GRAMMAR-GC (Genome-wide Rapid Association using the Mixed Model andRegression-Genomic Control)计算方法，应用R语言环境下GenABEL软件包和DMU软件对F2资源群体个体的头重、蹄重、板油重、背膘厚、胴体长、胴体重和屠宰体重7个性状进行全基因组关联分析。结果显示除胴体重外，其余6个指标均检测到了全基因组水平显著相关的SNP位点（P <1.03E–06），显著位点个数分别为头重63个、蹄重84个、板油重56个、屠宰体重8个、胴体长78个及背膘厚35个。这些显著位点均位于7号染色体上，几乎全部聚集于31Mb到49Mb范围内。3、通过单倍型分析、选择性清除分析方法对背膘厚GWAS显著区间进一步分析，将显著区间缩小至0.50Mb（34755605-35332315）区段，该区域内含有六个已有注释的基因（HMGA1、GRM4、NUDT3、RPS10、SPDEF和PACSIN1）。对这6个基因在两个试验群体（60d/150d/210d民猪、大白猪试验群体和60d二花脸猪、大白猪试验群体）背膘组织中进行荧光定量PCR分析，发现只有HMGA1mRNA有显著性的表达差异（P<0.05）。因此，HMGA1被确定为猪背膘厚的主效候选基因。4、对小鼠3T3-L1前体脂肪细胞系HMGA1基因进行了RNAi试验，对转染了siRNA的细胞和阴性对照细胞诱导分化后进行荧光定量试验，结果显示干扰后，HMGA1、C/EBP-β和PPARγ基因的mRNA表达量都显著下调（P<0.05）。此结果也说明了HMGA1在3T3-L1前体脂肪细胞分化为脂肪细胞的过程中发挥作用。更多还原

【Abstract】 This study analyzed the carcass traits from the genome level and the backfat trait was study indepth to screen the major candidate gene. The Large White×MinZhu F2resource group wasestablished and Genome-Wide Association Study (GWAS) was carried out using Illumina PorcineSNP60K DNA Chip for pig carcass traits. Then a significant area of backfat trait was in-depthanalyzed to screen major candidate gene. Research contents are as follows:1. The seven carcass traits containing head weight (HT), feet weight (FT), leaf fat weight (LFW),carcass length (CL), carcass weight (CW), backfat thickness (BFT) and slaughter body weight(SBW) were determined and described.2. According to the GRAMMAR-GC (Genome-wide Rapid Association using the Mixed Modeland Regression-Genomic Control) calculation method, GWAS were performed for HT, FT,LFW, CL, CW, BFT and SBW by using GenABEL under R-language environment and DMUsoftware in F2individual. The results showed the significant SNPs (P <1.03E–06) weredetected for six indexes, except of CW. The number of significant SNPs for HT, FT, LFW, CL,BFT and SBW were63,84,56,78,35and8respectively. All the significant SNPs werelocated on chromosome7and almost all were gathered in the31Mb to49Mb range,narrowing QTL range of carcass traits.3. The significant range of backfat trait was narrowed and located on chromosome70.50Mb(34755605-35332315) by haplotype analysis, selective sweep and P<0.01leve significantSNPs by GWAS. The narrowed range was blasted in Ensembl then six gene (HMGA1、GRM4、NUDT3、RPS10、SPDEF and PACSIN1), which have been annotated, were obtained.The fluorescence quantitative PCR for six genes were tested in backfat tissue of twoexperimental groups (60d/150d/210d old MinZhu and Large White pig test groups and60dold Erhualian pig and Large White pig test groups). The results showed HMGA1mRNA wasonly detected significant different expression. Therefore, HMGA1was identified as the majorcandidate for porcine backfat thickness.4. The RNAi test of HMGA1gene was performed on mouse3T3-L1preadipocyte cell lines.After induced differentiation for RNAi cells and negative control cells, cells were collectedand genes were tested by fluorescence quantitative PCR. Results showed that after interference, the mRNA expression of HMGA1、C/EBP-βand PPARγwere all significantlylowered (P<0.05). The results also showed that HMAG1played a role in3T3-L1preadipocytedifferentiating to adipocyte.更多还原